Flare stack combustion tip

ABSTRACT

A FLARE STACK COMBUSTION TIP HAVING A CENTRALLY DISPOSED GAS CONDUIT HAVING AN OPENING IN THE LOWER END THEREOF FOR COMMUNICATION WITH A FLARE STACK AND THE UPPER END THEREOF BEING AT LEAST PARTIALLY CLOSED, A PLURALITY OF SPACED APART GAS CONDUCTING CHANNELS EXTENDING OUTWARD FROM SAID GAS CONDUIT AND IN OPEN COMMUNICATION ALONG ONE END THEREOF WITH SAID GAS CONDUIT, AND A GAS EMISSION ORIFICE IN AN UPPER SEGMENT OF EACH OF SAID GAS CONDUCTING CHANNELS AND EXTENDING SUBSTANTIALLY THE ENTIRE LENGTH OF SAID UPPER SEGMENT, SAID GAS EMISSION ORIFICES BEING DISPOSED RADIALLY WITH RESPECT TO THE AXIS OF SAID GAS CONDUIT.

0a. 10, 1972 J. TURPIN Re. 27,501

FLARE STACK COMBUSTION TIP Original Filed July 22. 1968 I 4 Sheets-Sheet1 Q 2 INVENTOR.

YALEXANDER J. TURPIN ATTORNEY 1.972 v A. J. TURPIN 27507 FLARE STACKCOMBUSTION TIP Original Filed July 22. 1968 I 4 Sheets-Sheet 2 FIGURE 344 I? !s I5\ 37 35 15 I6 17 44 :9 7/7 /l9 1 v I FIGURE 4 INVENTOR.

ALEXANDER J. TURPIN BY 72% 7/. 0

ATTORNEY Oct. 10, 1972 v 1 Re. 27,507

, -FLARE STACK COMBUSTION TIP Original Filed July 22. 1968 4Sheets-Sheet 5 FIGURE 5 FIGURE 7 I N VENTOR.

ALEXANDER J. TURPIN BY ATTORNEY 0d. 10, 1972 TURPIN Re. 27,507

FLARE STACK COMBUSTION TIP Original Filed July 22, 1968 4 Sheets-Sheet 4FIGURE 9 I N VEN TOR.

ALEXANDER J. TURPIN BY ATTORNEY United" States Patent Oflice Re. 27,507Reissued Oct. 10, 1972 Int. Cl. F23b 5/00 US. Cl. 431202 13 ClaimsMatter enclosed in heavy brackets [II appears in the original patent butforms no part of this reissue specification; matter printed in italicsindicates the additions made by reissue.

ABSTRACT OF THE DISCLOSURE A flare stack combustion tip having acentrally disposed gas conduit having an opening in the lower endthereof for communication with a flare stack and the upper end thereofbeing at least partially closed, a plurality of spaced apart gasconducting channels extending outward from said gas conduit and in opencommunication along one end thereof with said gas conduit, and a gasemission orifice in an upper segment of each of said gas conductingchannels and extending substantially the entire length of said uppersegment, said gas emission orifices being disposed radially with respectto the axis of said gas conduit.

BACKGROUND OF THE INVENTION The present invention relates to thedisposal of gases by combustion. More particularly, the presentinvention relates to a flare stack combustion tip for the burning ofgases resulting from the operation of chemical plants and refineries andother operations which produce combustible gases which must be disposedof either continuously or intermittently.

Many chemical plants, refineries and other operations generate wastegases which must be disposed of in a safe and elfective manner. Oftenthese waste gases are merely by-products of a process and areconsistently produced in relatively constant volume. In other instances,because of upsets in plant operations, large quantities of gases such asfeed materials, intermediates or products must be disposed of quickly toprevent explosions or other hazardous condition from occurring in theplant. Regardless of source, however, the most commonly employed meansof disposing of waste gases in the combustion thereof, generally, bymeans of elevated flare stacks. The eflectiveness of this means ofdisposal of waste gases is largely dependent upon the efficiency of thecombustion tip aflixed to the upper end of the elevated flare stack.Combustion tip, as used herein, refers to that structure at the upperend of a flare stack and from which waste gases pass to the burningzone.

As a'result of the increasing emphasis placed on air pollution and theenactment of anti-pollution legislation in many states and otherpolitical subdivisions within the United States, one of the mostimportant criteria for a combustion tip is that it provide for theburning of Waste gases with little or no smoke production and thesubstantial elimination of odors and hazardous gases resulting fromincomplete combustion. While several flare stack combustion tips havebeen proposed for smokeless cornbustion of Waste gases, in general,these combustion tips are rather narrowly limited in the amount of wastegas which can be burned per unit time without smoke production. Theburning of waste gases without the production of smoke and with thealleviation of odors and hazardous gases escaping to the atmosphererequires complete combustion of such gases which in turn requires anadequate supply of oxygen for mixing with the Waste gases. In mostinstances, the failure to provide for such adequate supply of oxygen, asair, has been the major deficiency of the known combustion tips.

In addition to smokeless burning, another important criteria ofcombustion tips is'the ability to ignite and maintain igniton of thewaste gases. This becomes particularly important in those instanceswhere the waste gases are only periodically introduced into the flarestack. While pilot lights adjacent the combustion tip may serve toignite gases exiting the combustion tip, it is more eflicient andprovides greater safety it in addition, a continuous flame can bemaintained from the exit of the combustion tip. However, where wastegases are only periodically passed through the flare stack, to maintainsuch a continuous flame with conventional combustion tips is in mostinstances relatively expensive. This results from the fact that when nowaste gas is passing through the flare stack, the flame must bemaintained with gases other than waste gases and with the conventionalcombustion tips, relatively large quantities of such gases are requiredto maintain even a minimum continuous flame. To maintain combus tionwith these conventional combustion tips usually requires a minimum gasflow of approximately three percent and more often upwards of tenpercent of the maximum amount of gas which such tip is designed to burn.

In general, prior art combustion tips fail to provide for a fixed flamestand-oil from the exit of the tips. Thus, at periods of relatively lowgas flow, burning takes place immediately at the exit of the combustiontip while at periods of high gas flow, the flame is at a distance fromthe exit. Prolonged burning immediately adjacent the combustion tipresults in early deterioration of the metal parts of the tip. If flamingtakes place at too great a distance from the combustion tip, the flamemay not provide for complete combustion and is susceptible to beingeasily extinguished. It is desirable to maintain a substantially fixedflame stand-off from the exit of the combustion tip at an optimumdistance therefrom regardless of gas flowrate.

As a result of the design of conventional flare stack combustion tips,the pilot lights employed for ignition of the waste gases must belocated around the periphery of the flare nozzle. Therefore, to insureignition in areas of variable wind direction, a multiplicity of pilotsspaced around the periphery must be employed. Additionally, withconventional combustion tips, the pilot lights generally are extendedupward and inward beyond the flare tip and into the area through whicheflluent waste gas will pass. Therefore, during periods of gas flow, thewaste gas is continuously passing around and over the pilot light and atlow gas flow, the pilot light is within the flame of the burning gases.As a result, the pilot lights quickly deteriorate and fail and must bereplaced.

It is an object of the present invention to provide a new and improvedflare stack combustion tip.

Another object of the present invention is to provide a flare stackcombustion tip whereby large quantities of waste gases may be rapidlyburned with little or no smoke production.

It is also an object of the present invention to provide a flare stackcombustion tip whereby the escaping of odors and hazardous gases to theatmosphere during the burning of Waste gases is substantiallyalleviated.

An additional object of the present invention is to provide a flarestack combustion tip which provides for a continuous flame with asignificant reduction in fuel requirements as compared to conventionalcombustion tips.

Another object of the present invention is to provide a flare stackcombustion tip whereby waste gases are readily 1d effectively ignited onexciting the combustion tip :gardless of wind velocity and direction.

Still another object of the present invention is to prode a combustiontip which provides for a substantially xed flame stand-off from the exitof the tip.

Yet another object of the present invention is to provide flare stackcombustion tip which requires fewer pilot ghts and which allows anarrangement of pilot lights hereby a longer life for such pilot lightsresult.

A remaining object of the present invention is to prode a flare stackcombustion tip which remains cooler Jring combustion of waste gasesthereby reducing metal :terioration due to high temperatures.

Additional objects will become apparent from the folwing description ofthe invention herein disclosed.

SUMMARY OF THE INVENTION The present invention, which fulfills these andother )jBCtS, is a flare stack combustion tip comprising a cenallydisposed gas conduit having an opening in the twer end thereof forcommunication with a flare stack 1d the upper end thereof being at leastpartially closed, a lurality of spaced apart gas conducting channelsextend- .g outward from said gas conduit and in open comlunication alongone end thereof with said gas conduit, 1d a gas emission orifice in anupper segment of each E said gas conducting channels and extendingsubstanally the entire length of said upper segment, said gas nissionorifices being disposed radially with respect to re axis of said gasconduit.

DESCRIPTION OF THE DRAWINGS FIG. 1 of the drawings is a cross-sectionalview of an nbodiment of the combustion tip of the present inven- FIG. 2of the drawings is a top view of the embodient of the combustion tipillustrated in FIG. 1.

FIG. 3 of the drawings is a top view of a damper of the 'pe used in thecombustion tip of the present invention. FIG. 4 of the drawings is across-sectional view of a articularly useful embodiment of thecombustion tip of re present invention.

FIG. 5 of the drawings is an end cross-sectional view of gas conductingchannel of the combustion tip of the resent invention particularlyillustrating the pressure con 01 plate feature of said channel.

FIG. 6 of the drawings is a side elevational view of a is conductingchannel of the type illustrated in FIG. 5. FIG. 7 of the drawings is atop view of a gas conductlg channel of the type illustrated in FIGS. 5and 6.

FIG. 8 of the drawings is an end cross-sectional view E a flameretention feature of the combustion tip of the resent invention.

FIG. 9 of the drawings is a cross-sectional view of an nbodiment of thecombustion tip of the present inven on afiixed to the upper end of aself supporting flare ack.

DESCRIPTION OF THE PREFERRED EMBODIMENTS To describe the preferredembodiments of the combuson tip of the present invention, reference ismade to the :companying drawings. In the drawings, like characters reused throughout to designate like features.

Referring to the drawings, the combustion tip of the resent invention isshown affixed to the top of a standipe or flare stack 10. Flare stack 10may be supported by reams of guy wires or a surrounding derrick typestruclre or may be self supporting as is illustrated in FIG. 9. Thecombustion tip comprises a centrally disposed gas Jnduit 11 which isaffixed atop and in open communicaon with flare stack 10. Conduit 11 maybe generally ylindrical in shape but most often, as shown in thedrawlgs, has a lower segment 12 which is substantially cylinrical inshape and an upper segment 13 which is generalconical in shape, the apexof the cone representing the upper end of conduit 11. As will be morefully discussed below, the upper end of conduit 11 is completely closedto gas flow as illustrated in FIGS. 1 and 2 or only partially closed,the latter being preferred somewhat. By partially closed is meant thatthe area of the opening, if any, in the upper end of conduit 11 is lessthan the area of the opening in the lower end of conduit 11.

Flaring outward from upper segment 13 of conduit 11 are a plurality ofgas conducting channels 14. As viewed from an end thereof, channels .14appear flattened in shape presenting a rectangular appearance. Viewedfrom the side, channels 14 appear triangular in shape. Instead of thisflattened, triangular shape, however, channels 14 may take any number ofother configurations. For example, channels 14 may be generally roundedor elliptical as viewed from an end thereof and rectangular,parallelogram shaped or trapezoidal, etc., as viewed from the side.These channels 14 are in open communication along the entire basethereof with conduit 11 and serve to distribute or channel gas fromconduit 11 to the combustion zone. The number of channels 14 may varydepending upon the particular application of the present combustion tip.

The upper end or segment 15 of each of channels 14 contain a gasemission orifice 16 through which waste gas is discharged for burning,the orifices 16 being radially disposed with respect to the axis ofconduit 11. Orifice 16 extends substantially the entire length of upperend 15 though, if desired, it may extend a lesser distance and may becomprised of a plurality of spaced apart slotted or round openings.However, best results are achieved with the single slotted orifice 16extending the full length of upper end 15 of channels 14. Orifice 16often has a greater width at its outer end 17 than at its inner endwhich is a result of walls 18 of channels 14 being spaced further apartat the outer edge 19 of channels 14 than at the inner edge or point 20.Preferably, a lip section 21 which is attached to one wall 18 ofchannels 14 extends the entire length of upper end 15 partially closingend 15 to gas flow therethro ugh. By partially restricting waste gasflow through orifice 16, lip section 21 imparts turbulence to gasesdischarged from orifice 16, generally causing such gases to deviate atan angle of less than degrees from the normal upward flow path. Suchdeviation of the gas flow path from each of channels 14 imparts a cyclicmotion to the gases exiting the combustion tip. Such movement of theexiting waste gases aids in the induction and mixing of air with thewaste gases thereby promoting complete combustion. Additionally, theexiting waste gases are less affected by wind as a result of thisangular deviation in the effluent waste gas flow path.

As a result of the radial disposition of orifices 16 and the outwardextension of channels 14 with open area therebetween, air is morereadily induced into the burning zone and more intimately mixed with thewaste gases which, of course, results in a greater degree of smokelessburning and in significant alleviation of odors and hazardous gasesescaping to the atmosphere. In addition, the air passing betweenchannels 14 aids in cooling the metal surfaces of the channels therebyincreasing the useful life of such metals.

A damper 22 is provided as a feature of the combustion tip of thepresent invention. Damper 22 serves to prevent flashbacks within theflare stack and to reduce the quantity of gases required to keep theflare stack purged of explosive mixtures of waste gases and airresulting from periods when there is substantially no waste gas flowthrough the flare stack. Damper 22 is illustrated in the drawings asbeing positioned horizontally within a lower portion of lower segment 12of conduit 11. From the standpoint of manufacturing acomplete combustiontip unit and to hold any flashback that should occur as near the top ofthe flare as possible, such positioning is preferred. However, thedamper may be constructed into the flare stack well below the combustiontip.

Referring particularly to FIG. 3, damper 22 includes a plurality oftriangular gates 23 hinged to a radially disposed header 24. As the gaspressure below the damper 22 increases above a predetermined minimumvalue, gates 23 are pushed open by the gas to thereby permit gas to flowupward into the combustion tip. However, at very low gas pressures,gates 23 generally remain closed. In a prefered embodiment, damper 22 isprovided with one or more openings to permit limited gas flowtherethrough.

The above described damper 22 serves to prevent flashbacks within theflare stack by preventing the downflow of air into the flare stack whengates 23 are closed. Additionally, should an explosive mixture of wastegases and air form and flash within the combustion tip, the closure ofgates 23- will prevent the downward progression of the flashback intothe flare stack. By allowing limited gas flow through damper 22 eitheras a result of partial opening of gates 23 or by providing one or morefixed open ings in damper 22, upward gas flow is restricted such as toprovide higher gas velocities within the combustion tip which aids inpreventing formation of explosive waste gas and air mixtures within thecombustion tip. Additionally, by providing openings in damper 22, aflame can be maintained from the combustion tip despite gates 23 beingclosed.

' Primary ignition of the Waste gas is by pilot lights 25 positionednear orifices 16. Fuel for maintaining a flame in pilot lights 25 issupplied by means of pipes 26. Virtually any number of pilot lights maybe employed, however, because of the arrangement of the channels 14 ofthe combustion tip of the present invention, fewer pilot lights arerequired. Additionally, as will be more fully discussed below, one ofthe fatures of the present invention is the maintenance of continuousflame from the combustion tip itself with very low gas requirements,which substantially aids in insuring ignition of waste gases passingfrom the combustion tip. As a result of such features of the presentinvention, usually a single pilot light is adequate to insure ignitionwithout regard to wind direction and velocity. However, it is usuallydesirable to provide a second pilot light in order to insure ignition inthe event of failure of the first pilot light. These pilot lights 25 arepreferably positioned between channels -14 adjacent the confluence ofthe upper ends whereby regardless of the wind direction, gases will beblown across the pilot light flame and thereby ignited. The pilot lightspreferably do not extend above the upper ends 15 of channels 14 and,thus, do not extend into the waste gas eflluent from such channels 14.The design of the combustion tip of the present invention permits pilotlights so positioned to elfectively ignite waste gases exiting thecombustion tip. The particular type of pilot light used is notparticularly critical to the present invention and any of those commonlyemployed for such utility may be used.

In a most useful embodiment of the present invention (see particularly'FIGS. 5, 6 and 7), channels 14 of the combustion tip are provided withhinged pressure control plates 27 which provide for substantiallycomplete closure of orifices 16 during periods of low gas flow.Preferably, pressure control plates 27 are hinged to a wall 18 ofchannel 14 opposite the wall to which lip section 21 is attached.Usually, pressure control plate 27 is hinged to wall 18 at a point belowthe upper edge thereof and such as to extend upward across channel =14to thereby extend through orifice 16 and in closed position, to restagainst lip section 21. The means of hinging pressure control plate 27to wall 18 preferably comprises two or more lugs 28 which extend fromthe base 29 of pressure control plate 27 through slots 30 in wall 1 8.Lugs 28 terminate exterior of channel 14 in a head 31 having a diameterwhich is greater than the width of slots 30. To prevent the leakage ofgas through slots 30 in wall 18, caps 32 are provided on the outside ofwall 18 to cover slots 30 and form a leakproo-f chamber 33 in which head31 works andin which any gas passing through slots 30 is contained.

By means of pressure control plate 27, a substantially constant velocityfor the gases exiting orifices 16 can be maintained over a wide range ofgas flows. Without pressure control plate 27, as gas pressures and flowsvary within channels 14 and flare stack 10, the velocity of the gasespassing from orifices 16 will vary as will in turn, the distances offlame stand-elf from the orifices 16. Without pressure control plates 27and during periods of low gas pressure, gas velocity through orifice 16will be low and burning will occur substantially at orifice 16 which, asnoted above, will result in extreme heating of the metal surfacesadjacent orifice 16 which in turn significantly shortens the useful lifeof such metal surfaces. Through the use of pressure control plates 27,even at low gas flows, suflicient exit gas velocities can be maintainedto provide for a significant flame stand-01f from orifices 16 andbecause pressure control plate 27 raises proportionally toincreases ingas flow thereby increasing the open area of orifices 16, substantiallythe same flame stand-01f is maintained through a substantial increase ingas flow within flare stack 10. Pressure control plate 27 also aids inpreventing flashbacks within the combustion tip by serving toincreasegas velocities above the combustion tip thereby preventing air frompassing into the combustion tip.

Pressure control plate 27 preferably is designed such that it does notcompletely close gas flow through orifice 16 even when in fully closedposition. In this embodiment, pressure control plate 27 does not extendto the outer end of orifice 16 thereby leaving a space 34 adjacent theouter end of orifice 16 through which gas can continuously flow.Pressure control plate 27 is sized and shaped such that space 34 issuflicient to permit just enough gas to pass therethrough to maintain aminimum flame adjacent the outermost corner of channels v14. By suchdesign of pressure control plate 27, only a very small amount of gas isrequired to maintain a continuous flame as compared to the large amountsof gas which ultimately can be burned as the pressure control plates 27are fully opened. It is, of course, desirable tomaintain a continuousflame at the exits of the combustion tip for greater safety andefliciency in ignition of the waste gases.

A further means of providing a continuous flame from the combustion tipis illustrated in FIG. 4. This means includes a conical valve member 35and a valve seating ring 36. An annular opening 37 between valve seatingring 36 and conical valve member 35 is provided whereby when valvemember 35 is seated with respect to valve seating ring 36, gas will bepermitted to flow between valve member 35 and valve seating ring 36.Generally, annular opening 37 has a radial distance of no less than ofan inch and seldom more than A of an inch when valve member 35 isseated.

A tubular anchor pipe 38 extends downwardly from the apex of conicalvalve member 35 and is slidably engaged for limited vertical movementwith flow pipe 39' which is coaxially aligned with conduit 11 but ofsubstantially less diameter than conduit 11. The limited verticalmovement of anchor pipe 38 is provided by an elongated opening 40through anchor pipe 38 and bolt 41 which extends across flow pipe 39through elongated opening 40. Such arrangement limits the verticalmovement of anchor pipe 38 and in turn, the vertical movement of valvemember 35, to a distance equal to the vertical length of elongatedopening 40. Additionally, as shown in FIG. 4, the resting of the upperedge of elongated opening 40 on the upper surface of bolt 41 serves toposition valve member 3 5 with respect to valve seating ring 36 in suchmanner as to provide annular opening 37. However, annular openings 37may be formed by means other than elongated opening 40 and bolt 41 suchas for example, by means of a plurality of lugs extending from valveseating ring 36 toward the center thereof upon which valve member 35 mayrest or by a plurality of lugs extending from the conical surfaces of211% member 35 which will rest upon surfaces of valve eating ring 36.

Flow pipe 39 preferably extends through damper 22 to 110W for flow ofgas up through the combustion tip even vhen the gas pressures in flarestack 10 are too low to :pen gates 23 of damper 22. Such gas flow passesupvard through flow pipe 39 and around valve member 5 and throughannular opening 37 whereupon the gases re burned. In such manner, acontinuous flame can be Jaintaned at the top of the combustion tip evenwith mounts of gas too small to open gates 23 of damper ,2. As the gasflow through the flare stack increases, valve member 35 is forced upwardthereby increasing the radial vidth of annular opening 37 to permit moregas to pass the combustion area. Valve member 3 5 is designed in veightand cooperation with the limited vertical movenent permitted by theattachment of tubular anchor pipe 8 to flow pipe 39 such that atapproximately the presure required to raise valve member 35 to its fullheight rom seating ring 36, pressure control plates 27 begin 0 openthereby permitting gas flow through orifices 16 which gas is thenignited by the flame resulting from the :ases passing through annularopening 37 and the space v4 adjacent the outermost edge of channels '14.

The conical valve member 35 may be replaced with a ubstantially flatplate valve member which functions as vbove described. Also, in manyinstances, circumstances may not make attractive the use of a variableopening 'alve means in the upper end of conduit 11 In such intances, acircular plate or a conical member as described .bove may be fixedlypositioned in the upper end of onduit 11 in such manner as to providev afixed size anlular opening around the periphery of said plate or mem-D61. With respect to the discussions herein of the annular vpening it isto be understood that the term applies not nerely to a substantiallycontinual open space surroundng conical valve member 35 but alsoincludes a plurality vf spaced channels annularly arranged about thesurface f valve member 35 or other such arrangement.

In most instances, it is desirable to have a shroud 42 mounted toencircle conduit 11 and channels 14. While hroud 42 may be generallycylindrical in shape as shown n FIG. 1, it is preferably venturi shapedas illustrated in IG. 4. Shroud 42 usually extends well below thelowernost point of channels 14 and slightly above or approximately equalin heighth with the uppermost portions of :hannels 14. By maintainingthe upper edge of shroud l2 only slightly above or in substantially thesame hori- ;ontal planeas the uppermost segments of channels 14, heformation of a potential combustion chamber Within hroud 42 issubstantially avoided. Should shroud 42 exend a substantial distanceabove the uppermost segments of channels 14, waste gases and air canreadily ac- :umulate within the confines of the shroud and upon igniion,can destroy the shroud and possibly the combusion tip. Generally, shroud42 is positioned with respect 0 conduit 11 and channels 14 by means oflower supiorting plates 43 attached to conduit '11 and upper plates l4attached to the outermost edges of channels 14. The irimary purposes ofshroud 42 are to aid in the inducion of air into the flame area and toprotect pilot lights '.5 and the continuous flame generated during lowgas lows through conduit 11 and channels .14 from wind urrents.

Referring particularly to FIGS. 4 and 8, the upper lates '44 attachingshroud 42 to channels 14 are deigned to serve a secondary and quiteuseful purpose. In uch design, these upper plates are a substantially V-haped member attached to channels 14 and shroud 42 uch that the apex ofthe V is just below the outermost :dge of channels 14. Such arrangementresults in formaion of a receptacle or cup in which gases may collectind burn in cooperation with the flame permitted by pace 34 duringperiods of low gas flow thereby aiding n the retention of a continuousflame from the combustion tip. This V-shaped design of upper plates 44is particularly useful in large combustion tips wherein there is aconsiderable distance between the outer end of orifices ])6 and pilotlights 25 adjacent the confluence of the upper ends of channels 14 orthe valve member 35, if such is provided.

To aid in the induction'of air into the combustion zone, it isfrequently desirable to direct high pressure steam upward along andaround the outer surfaces of the conduit 11 and channels 14. In someinstances, air may be forced into the combustion zone by means ofblowers and the like. One such means for supplying forced air to thecombustion zone is described below in reference to FIG. 9. When usinghigh pressure steam to induce air to flow into the combustion zone, asteam conducting ring 45 is disposed around and substantially coaxialwith conduit .11 adjacent the lower edge of shroud 42, usually justbelow such lower edge. Steam conducting ring 45 is connected to a sourceof high pressure steam by means of steam line 46. To distribute the highpressure steam upward around the surfaces of conduit 11 and betweenchannels 14 and secure maximum air induction, a plurality of spacedapart steam nozzles '47 are connecting to steam conducting ring 45 andpositioned to direct a jet of steam upward between and around channels14. As a practical matter, a considerable distance, usually severalfeet, will separate the steam nozzles 47 and the actual combustion zonein order to obtain a maximum air induction into the burning area. Theexact distance will, of course, vary with the size of the combustiontip, steam pressure, normal flame standolf, and other such factors andcan readily be determined by those skilled in the art.

Referring specifically to FIG. 9, the combustion tip of the presentinvention is shown affixed to the top of a self supporting flare stackwhich has a primary centrally disposed waste gas conduit 48 which issurrounded by a coaxially aligned annular air conduit 49. Such conduitwithin a conduit arrangement along with the attendant spacing plates(not shown) provide a flare stack which requires little or no supportingstructures to maintain it in an upright position. With such flare stack,generally all of the primary air required to secure substantiallycomplete combustion of the waste gasis provided by forcing air upthrough conduit 49. Primary air is that air not normally available inthe combustion zone and which must be induced to flow from surroundingareas or forced from other sources to such combustion zone. The air maybe generated by blowers in the lower portion of air conduit 49 or may beintroduced into air conduit 49 by one or more transporting pipes 5!connecting air conduit 49 to an air source. As the air passes upwardthrough air conduit 49, it passes up and around conduit 11 and channels14 and into the combustion area. While a shroud 42 is provided aroundthe combustion tip, this shroud is in reality merely an expandeddiameter extension of air conduit 49. If desired, this shroud 42 may beseparated from air conduit "49 in such manner as to permit the inductionof atmospheric air under the shroud as a complement to the air passingupward through air conduit 49.

What is claimed is:

1. A flare stack combustion tip comprising a centrally disposed gasconduit having an opening in the lower end thereof for communicationwith a flare stack and the upper end thereof being at least partiallyclosed, a plurality of spaced apart gas conducting channels extendingoutward from said gas conduit and in open com munication along one endthereof with said gas conduit,

and a gas emission orifice in an upper segment of each of said gasconducting channels and extending substantially the entire length ofsaid upper segment, said gas emission orifices being disposed radiallywith respect to the axis of said gas conduit and being partiallyrestricted by means of a lip section extending the entire length thereoffrom a wall of said gas conducting channel.

2. The flare stack combustion tip of claim 1 wherein said gas conduit iscomprised of a lower substantially cylindrical section and an upperconical shaped section from which, said gas conducting channels extend.

3. The flare stack combustion tip of claim 1 wherein a shroud iscoaxially aligned with said gas conduit and extends downward fromadjacent the upper edge of said gas conducting channels to thereby atleast partially surround said gas conduit and said gas conductingchannels.

4. The flare stack combustion tip of claim 3 wherein said shroud isattached adjacent its upper end to an outer edge of said gas conductingchannels by means of a V-shaped member having the apex of the V belowthe upper edge of said gas conducting channel.

5. The flare stack combustion tip of claim 3 wherein said shroud isventuri shaped.

6. The flare stack combustion tip of claim 1 wherein a pressure controlplate is rotatably connected to a wall of each of said gas conductingchannels such as to extend across said gas emission orifices andrestrict gas flow therethrough, said pressure control plates rot'atablyresponsive to gas flows within said gas conducting channels.

7. The flare stack combustion tip of claim 6 wherein said pressurecontrol plate does not extend the entire length of said gas emissionorifice thereby leaving a space adjacent the outer end of said gasemission orifice for the escape of gas from said gas conductingchannels.

8. The flare stack combustion tip of claim 1 wherein said gas conduitincludes in a lower portion thereof a damper comprising a plurality ofgenerally triangular shaped gates hinged to radially disposed headersand rotatably responsive to gas pressures from either side thereof.

9. The flare stack combustion tip of claim 1 wherein said gas conduitterminates at its upper end in a valve seating ring having a conicalmember seated therein in spaced apart relation, said conical valve beingmovably responsive in a vertical direction to gas flow from below.

10. The flare stack combustion tip of claim 1 wherein means is providedfor the injection of high pressure steam adjacent the lower end of saidgas conducting channels and in an upward direction.

11. A flare pipe combustion tip comprising an annular shroud-formingcasing open at its ends for passage of air thereinto and therethrough, agas conduit extending substantially through said casing and having anopen inlet end for communication with a flare pipe and an outlet endwithin the exit portion of said casing, channel means communicating withthe exit portion 09 said conduit and extending therefrom substantiallyacross said casing, emission orifice means disposed along the exitportion of said channel means for mixing gas emerging from said conduitwith ambient air, and pilot means for igniting the dis charged gas andair mixture.

12. A combustion tip as described in claim. 11 wherein said gas conduitis concentrically disposed within said casing and said channel meanscomprises a plurality of arms radiating therefrom between which air insaid casing passes for contact with gas emerging from said restrictedorifice means.

13. A combustion tip as described in claim 12 further including upwardlyopening flap valve plate means yieldingly mounted in said conduit torestrict the admission of air thereinto and the emission of gastherefromr.

References Cited The following references, cited by the Examiner, are ofrecord in the patented file of this patent or the original patent.

UNITED STATES PATENTS 2,537,091 1/1951 Rodman et al. 431202X 2,734,5622/ 1956 Haberle et a1. 431202X 2,761,496 9/ 1956 Verner et al 43 l2023,289,729 12/1966 Reed 431-202 3,429,645 2/ 1969 Reed 431-202 FOREIGNPATENTS 1,226,272 2/1960 France 431-202 EDWARD G. F'AVORS, PrimaryExaminer U.S. Cl. X.R. 23-277 C

